Drill bit steering assembly

Abstract

In one aspect of the present invention, a steering assembly for downhole directional drilling comprises an outer bit comprising a bore and an outer cutting area and in inner bit comprising an inner cutting area and connected to a shaft that is disposed within the bore. At least one biasing mechanism is disposed around the shaft. At least one fluid channel is disposed within the outer bit and redirects fluid to the at least one biasing mechanism causing the at least one biasing mechanism to push the shaft and alter an axis of the inner bit with respect to an axis of the outer bit.

What is claimed is: 
     
       1. A steering assembly for downhole directional
 drilling, comprising: 
 an outer bit comprising a bore and an outer cutting area; 
 an inner bit comprising an inner cutting area and connected to a shaft that is disposed within the bore; 
 at least one biasing mechanism disposed around the shaft; 
 at least one fluid channel disposed within the outer bit and which directs fluid to the at least one biasing mechanism causing the at least one biasing mechanism to push the shaft and alter an axis of the inner bit with respect to an axis of the outer bit such that the inner bit contacts a formation at a different angle than the outer bit contacts the formation; and 
 a ring, disposed within the bore of the outer bit, configured to act as a buffer between the shaft and the at least one biasing mechanism. 
 
     
     
       2. The assembly of  claim 1 , wherein the at least one biasing mechanism comprises an expandable element configured to expand and push the shaft to alter the axis of the inner bit. 
     
     
       3. The assembly of  claim 2 , wherein the expandable element comprises a composite, rubber, metal, ceramic, and combinations thereof. 
     
     
       4. The assembly of  claim 1 , wherein the at least one biasing mechanism comprises a piston configured to slide within a chamber and push the shaft to alter the axis of the inner bit. 
     
     
       5. The assembly of  claim 1 , wherein the at least one biasing mechanism comprises a ball configured to roll within a cylinder and push the shaft to alter the axis of the inner bit. 
     
     
       6. The assembly of  claim 1 , wherein the ring comprises one continuous body. 
     
     
       7. The assembly of  claim 1 , wherein the ring encloses the at least one biasing mechanism so to protect the at least one biasing mechanism from drilling fluid disposed within the bore. 
     
     
       8. The assembly of  claim 1 , wherein the ring is directly connected to the bore and configured to slide radially due to pressure from the at least one biasing mechanism. 
     
     
       9. The assembly of  claim 1 , wherein the ring is axially fixed within the bore. 
     
     
       10. The assembly of  claim 1 , wherein the ring comprises a plurality of vanes axially disposed intermediate a plurality of biasing mechanisms wherein the at least one biasing mechanism comprises a pressure region defined by the plurality of vanes. 
     
     
       11. The assembly of  claim 1 , wherein the ring is directly connected to a piston that is configured to slide within a chamber and force the ring to push the shaft and alter the axis of the inner bit. 
     
     
       12. The assembly of  claim 1 , wherein at least three biasing mechanisms are equally spaced around the shaft. 
     
     
       13. The assembly of  claim 1 , wherein the inner bit is configured to rotate in a same direction as the outer bit. 
     
     
       14. The assembly of  claim 1 , wherein the inner bit protrudes from the outer bit. 
     
     
       15. The assembly of  claim 1 , wherein the fluid is drilling fluid. 
     
     
       16. The assembly of  claim 1 , further comprising a valve disposed within the at least one fluid channel and configured to control fluid to the at least one biasing mechanism. 
     
     
       17. The assembly of  claim 1 , further comprising at least one fluid nozzle disposed on the inner cutting area or a gauge portion of the inner bit. 
     
     
       18. The assembly of  claim 1 , wherein the outer bit is rigidly connected to a drill string and the inner bit is rigidly connected to a torque transmitting device disposed within the bore. 
     
     
       19. A method of steering a downhole drill string,
 comprising: 
 providing an outer bit comprising a bore and an outer cutting area, an inner bit comprising an inner cutting area and connected to a shaft that is disposed within the bore, at least one biasing mechanism disposed around the shaft, least one fluid channel disposed within the outer bit, and a ring disposed within the bore of the outer bit configured to act as a buffer between the shaft and the at least one biasing mechanism; 
 deploying the drill string within a wellbore; 
 redirecting a fluid through the at least one fluid channel to the at least one biasing mechanism; and 
 pushing the shaft of the inner bit with the at least one biasing mechanism such that the inner bit contacts a formation at a different angle than the outer bit contacts the formation.